/* CoralCube | Massively Multiplayer Online Role-Playing Game(MMORPG) Emulator.
|* 
|* Copyright (C) 2005-2010 MaNGOS <http://getmangos.com/>
|*               2008-2010 TrinityCore <http://www.trinitycore.org/>
|*               2008-2010 CoralCube <http://www.CoralCube.com/>
|*
|* This program is free software. You can redistribute it and/or modify it under the terms of 
|* the GNU General Public License as published by the Free Software Foundation, either 
|* version 2 of the License.
|*
|* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY, 
|* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
|* See the GNU General Public License for more details.
|*
|* You should have received a copy of the GNU General Public License along with this program. 
|* If not, see <http://www.gnu.org/licenses/>.
|*/

#include "Cryptography/BigNumber.h"
#include <openssl/bn.h>
#include <algorithm>

BigNumber::BigNumber()
{
    _bn = BN_new();
    _array = NULL;
}

BigNumber::BigNumber(const BigNumber &bn)
{
    _bn = BN_dup(bn._bn);
    _array = NULL;
}

BigNumber::BigNumber(uint32 val)
{
    _bn = BN_new();
    BN_set_word(_bn, val);
    _array = NULL;
}

BigNumber::~BigNumber()
{
    BN_free(_bn);
    if (_array) delete[] _array;
}

void BigNumber::SetDword(uint32 val)
{
    BN_set_word(_bn, val);
}

void BigNumber::SetQword(uint64 val)
{
    BN_add_word(_bn, (uint32)(val >> 32));
    BN_lshift(_bn, _bn, 32);
    BN_add_word(_bn, (uint32)(val & 0xFFFFFFFF));
}

void BigNumber::SetBinary(const uint8 *bytes, int len)
{
    uint8 t[1000];
    for (int i = 0; i < len; i++) t[i] = bytes[len - 1 - i];
    BN_bin2bn(t, len, _bn);
}

void BigNumber::SetHexStr(const char *str)
{
    BN_hex2bn(&_bn, str);
}

void BigNumber::SetRand(int numbits)
{
    BN_rand(_bn, numbits, 0, 1);
}

BigNumber BigNumber::operator=(const BigNumber &bn)
{
    BN_copy(_bn, bn._bn);
    return *this;
}

BigNumber BigNumber::operator+=(const BigNumber &bn)
{
    BN_add(_bn, _bn, bn._bn);
    return *this;
}

BigNumber BigNumber::operator-=(const BigNumber &bn)
{
    BN_sub(_bn, _bn, bn._bn);
    return *this;
}

BigNumber BigNumber::operator*=(const BigNumber &bn)
{
    BN_CTX *bnctx;

    bnctx = BN_CTX_new();
    BN_mul(_bn, _bn, bn._bn, bnctx);
    BN_CTX_free(bnctx);

    return *this;
}

BigNumber BigNumber::operator/=(const BigNumber &bn)
{
    BN_CTX *bnctx;

    bnctx = BN_CTX_new();
    BN_div(_bn, NULL, _bn, bn._bn, bnctx);
    BN_CTX_free(bnctx);

    return *this;
}

BigNumber BigNumber::operator%=(const BigNumber &bn)
{
    BN_CTX *bnctx;

    bnctx = BN_CTX_new();
    BN_mod(_bn, _bn, bn._bn, bnctx);
    BN_CTX_free(bnctx);

    return *this;
}

BigNumber BigNumber::Exp(const BigNumber &bn)
{
    BigNumber ret;
    BN_CTX *bnctx;

    bnctx = BN_CTX_new();
    BN_exp(ret._bn, _bn, bn._bn, bnctx);
    BN_CTX_free(bnctx);

    return ret;
}

BigNumber BigNumber::ModExp(const BigNumber &bn1, const BigNumber &bn2)
{
    BigNumber ret;
    BN_CTX *bnctx;

    bnctx = BN_CTX_new();
    BN_mod_exp(ret._bn, _bn, bn1._bn, bn2._bn, bnctx);
    BN_CTX_free(bnctx);

    return ret;
}

int BigNumber::GetNumBytes(void)
{
    return BN_num_bytes(_bn);
}

uint32 BigNumber::AsDword()
{
    return (uint32)BN_get_word(_bn);
}

bool BigNumber::isZero() const
{
    return BN_is_zero(_bn)!=0;
}

uint8 *BigNumber::AsByteArray(int minSize, bool reverse)
{
    int length = (minSize >= GetNumBytes()) ? minSize : GetNumBytes();

    if (_array)
    {
        delete[] _array;
        _array = NULL;
    }
    _array = new uint8[length];

    // If we need more bytes than length of BigNumber set the rest to 0
    if (length > GetNumBytes())
        memset((void*)_array, 0, length);

    BN_bn2bin(_bn, (unsigned char *)_array);

    if (reverse)
        std::reverse(_array, _array + length);

    return _array;
}

const char *BigNumber::AsHexStr()
{
    return BN_bn2hex(_bn);
}

const char *BigNumber::AsDecStr()
{
    return BN_bn2dec(_bn);
}
